Tekken Tag Tournament 2 Tips

To play as the hidden character Devil Kazuya, simply place your cursor over Kazuya at the character selection screen in any game mode then press Left or Right + Up + Circle + Triangle at the same time.

Edit: You have to actually enter and be playing during any fight mode. Otherwise while fighting simply push either up and towards your opponent or up and away while pressing both punch buttons at the same time he should flash and turn into devil kazuya. This should simplify things for you. Quite easy to do enjoy